Performance evaluation of once-through steam generator of a 626 MW supercritical oil-fired steam power plant under a variable operating load

Abstract

Unforeseeable growth in the global population needs growing technological advances in establishing power plants to overcome this critical issue by reducing greenhouse gases. In the present study, a thermodynamic analysis for a 626 MW supercritical oil-fired steam power plant under different operating loads of 50%, 75%, 100%, and 105% at a sliding-pressure operation is conducted. Based on the actual operation of the examined plant, the results show that the condenser has the highest energy loss. As well, at a 100% full load, 88.6% of the total exergy is destructed in the once-through steam generator, followed by the turbine, and then the condenser. Hence, a significant concern is introduced toward the steam generator since it has the largest exergy destruction percentage relative to other cycle components. The heat transfer sets inside a once-through steam generator are studied and analyzed. The exergy destruction in the combustion process represents 58.6% and 54% of the overall boiler exergy destruction at an operating load of 50% and 100%, respectively. In addition, the evaporator has higher exergy destruction in comparison with other heating surfaces in the furnace.